Well tools and gripping members therefor



United States Patent [72] Inventors Marion D. Kilgore Houston; Robert C.Pumpelly, Dallas, Tex. I21] Appl. No. 776,110 [22] Filed Nov. 15,1968[45 Patented Dec.22, 1970 [73] Assignee Dresser-Industries, Inc.

Dnllns,'lex. a corporation of Delaware [54] WELL TOOLS AND GRIPPINGMEMBERS THEREFOR 43 Claims, 31 Drawing Figs. [52] U.S. 166/216, 166/134,166/139,166/217 [51] lntJ 1221b 23/00 [50] Field ofSearch 166/206,209,118, 75, 85, 88,138,139,136, 137, 214,134, 216,217

. [56] References Cited UNITED STATES PATENTS 615,321 12/1898 Straubetal 166/214 2,076,314 4/1937 Zschokke... 166/134 3,161,424 12/1964 Maass166/85 1 7 4 4/ 29 PFlWdzz-r /214 3,250,331 5/1966 Boyle 166/2173,352,363 11/1967 Bennett 166/214 3,416,610 12/1968 Prescott, Jr 166/206Primary Examiner-James A. Leppink Attomeys-Robert W. Mayer, DanielRubin, Peter J. Murphy,

Frank S. Troidl, Roy L. Van Winkle, Roderick W. Mac Donald and WilliamE. Johnson, Jr.

ABSTRACT: A slip or gripping member that is used on well tools to lockthe well tools at a desired location in a well bore.

The slip is movably mounted on the well tool and is provided with wallengaging teeth on relatively opposite sides thereof adjacent to eachend. The wall engaging teeth are separated on the slip by a distancethat is greater than the diameter of the well bore so that movement ofthe slip to an angular position brings the teeth into engagement withthe well bore wall.

Relatively movable abutments are provided on the well too] wPATENTEUADECZZIHYB SHEET 01 0F INVENTOKS,

@KWMAM ATTOIQNEY 1 WELL rooLsANn GRIPPING MEMBERS THEREFOR BACKGROUND orTHE-INVENTION Slips heretofore utilized on' oil well tools have had atoothed exterior and a. tapered interior. The tapered interior mateswith an exterior taping surface o'n-a wedge or expander member that isforced underneath the slip to radially expand the slips forcing thetoothed surface into 'holdingengagement with the well bore wall.Generally, the expander member is an annular frustoconical member'ofunitary construction-while the slips are constructed from a plurality ofsegments. Some slips are constructed from a single annular ring of amaterial that fractures into segments when the wedge is forcedthereunder.

Such slips havebeen generally satisfactory as an operational member inthe well tools. However, the utilization of such slips does require themachining of both the wedge and the slips.

Thus, such slips are relatively expensive to manufacture.

Also, it is highly desirable to. maintain the well tools on whichtheslips are used to the shortest possible length. Slips having a doubletapered interior surface operating with a pair of oppositely taperedexpanders-canbe utilized to hold the tool against movement in the wellbore in both directions. The overall length of the combination isconsiderably longer than desirable. Also, in the double holding-typeslip, there is again presenteda relatively complex arrangement since theslips, two expanders, and means for retaining the segmented slips on theexpanders must be'provided. i

As will be appreciated'by those skilled in the well tool art, theslip-expander combination will hold the well too] against movement inthe well bore provided that the actuating mechanism which forces;, t heexpander into engagement with the slip is not removed therefrom. If theforce is released on the expander, the segmented slips can collapseinwardly and vide a slip that remains set until positively released.

As well tools utilizing the tapered-segmented slips are run.

into the well bore, the segmented slips are exposed to the action of thefluid in1the well bore and may be moved slightly outwardly where theycan engage the well bore wall,'-the conduit wallor a discontinuityin thewell bore or the conduit. When this occurs, the segmented slips aresometimes torn loose from the well tool resulting in the loss of theslips into the well bore and thus-preventing the proper operation of thewell tool in the well bore when the desired location is reached. Theloss of the slips into the well bore may necessitate an extremelyexpensive fishing job to remove the slips from the well Theaforementioned problems are even more prevalent when the well tool isdesigned for use in very small bores or slim holes. In the small boretools, the space available for the slips and expanders is greatlyreduced. Thus, the slips must be constructed with less thickness and,'correspondingly, the slips will be much more fragile. g

From'the foregoing, it will be apparent that the most desirable form ofslip for use in a well tool is one that is positive in its holdingengagement with the -well bore, will hold until positively released, canbe mounted and actuated in the shortest possible length on the'well',tool, and is of the simplest and strongest construction possible.

. SUMMARY or rns INYENTION Arranged to engage the-wall of the well boreto hold the well too in the well bore. The slip comprises a body memberhavr in first and second ends, a wall engaging portion adjacent luof theends, a distance between the wall engaging poring greater than thediameter of the well bore whereby W all engaging portions canengage thewell bore wall and aportion intennediate the ends having a dimensionless than the diameter of thewell bore, wherebythe well tool can movetherethrough.

In another aspect,'this invention provides an improved well tool usefulin a well bore, the tool comprising: an elongated body movablelongitudinally through the well bore; a gripping member or slip carriedby the body andhaving first and second ends, a first dimension smallerthan diameter of the well bore, a second dimension larger than thediameter of the well bore, and wall engaging portions adjacent each endspaced by a distance including the second dimension; means forsupporting the gripping member on the body for movement between aretracted position wherein the gripping member is out of engagement withthe well bore wall and a holding position wherein the gripping member isin engagement with thewell bore wall; and, means for moving the grippingmember between the holding and retracted positions.

One object of the invention is to' provide an improved slip structureofunitary construction.

The foregoing and additional objects and advantages of the inventionwill become more apparent as the following detailed description is readin conjunction with the accompanying drawings.

. BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a view, partly in crosssection and partly in elevation, of a single-slip anchor shown in theunset condition in the well bore.

FIG. 2 is a view similar to FIG. 1 but illustrating the anchor in theset condition inthe well bore.

FIG. 3 is 'a horizontal cross section taken generally along the line 3-3of FIG. 1.

FIG. 4 is an enlarged elevation view of a slip constructed in accordancewith the invention.

FIG. 5 is a cross section of the slip of FIG. 4 taken along the line 5 5of FIG. 4. 1

FIG. 6 is a top end view of the slip of FIG. 4.

FIG. 7 is an auxiliary bottom end view of the slip of FIG. 4.

FIGS. 8A and 8B, taken together, form a view partly in cross section andpartly in elevation; of a mechanicallyactuated packer in the unsetcondition. I

FIG. 9 is a layout of a .I-slot utilized in the packer illustrated inFIGS. 8A and 8B.

FIGS. 10A and 10B, taken togethenform a view similar to FIGS. 8A and 8B,but illustrating the packer in the set condition.

FIG. 11 is a view, partly in elevation and partly in cross section, of aportion of the packer shown in FIG. 8A and 8B in a different stage ofoperation.

FIGS. 12A and 12B, taken together, form a view, partially in crosssection and partially in elevation, of a two-slip anchor in the unsetcondition.

FIG. 13 is a view, partly in cross section and partly in elevation, of aportion of the anchor of FIGS. 12A and 128 in another operatingposition.

FIG. 14 is a horizontal cross section taken along the line l4-l4 of FIG.13.

FIGS. 15A, 15B and 15C, taken together, form a view. partly in elevationand partly in cross section, of a hydraulically-actuated packer in theunset condition.

FIGS. 16A, 16B and 16C, taken together, form a view similar to FIGS.15A, 15B and 15C but showing the packer in the set condition.

FIGS. 17A and 17B, taken together, form a view, partly in elevation andpartly in cross section, of a bridge plug arranged DESCRIPTIONOF THEEMBODIMENT OF FIGURE I Referring to the drawings and to FIG. 1 inparticular, shown therein and generally designated by the referencecharacter 30 is a single slip, anchor assembly that is positioned in acasing 32 located in a well bore 34. While the anchor assembly 30 willmost frequently be used within a conduit, such as the casing 32, itshould be understood that the anchor assembly-30 may also be utilizedwithin a well bore having no conduit disposed therein.

The anchor assembly 30 includes an elongated body or mandrel 36 thatextends therethrough. The mandrel 36 is arranged at its upper end forconnection with 'a tubing string 38 that extends into well bore 34 fromthe surface of the well.

The lower end of the elongated member 36 is also arranged to beconnected with other well apparatus. As illustrated in FIG. 1, the lowerend of the mandrel 36is connected with a tubular member 40. Intermediateits ends, the mandrel 36 is provided with a relatively short length ofmale thread 42. The male thread 42 mates with a longer femalethr ead- 44that is formed in the interior of an upperhead member 46.

A plurality of how springs 48, or other suitable means for frictionallyengaging the interior wall. of the casing 32, are provided on theexterior of the upper head 46. The frictional engagement between the bowsprings 48 and the interior wall of the casing 32 permits relativerotation between the mandrel 36 and the upper head 46. The lower end ofthe upper head 46 has a downwardly facing shoulder or abutment 50 thatis arranged to engage a gripping member or slip 52 for reasons that willbecome more apparent'as the'description proceeds. An annular recess 51in the upper head 46 provides a downwardly facing shoulder 53 andan'upwardly facing shoulder 54 near the lower end thereof.

The shoulder 54 is illustrated as being in engagement with an annularabutment 56 that is carried by the upper end of a slip sleeve 58. Theslip sleeve 58 slidingly encircles the mandrel 36 and extends downwardlythrough the slip 52.

At its lower end, the slip sleeve 58 has an annular abutment 60 arrangedto engage a downwardly facing shoulder 62 formed in a lower head 64. Apair of diametrically opposed slots 66 (both slots 66'are shown in FIG.3) are provided in the slip sleeve 58 to receive pivot lugs or pins 68that are mounted in the slip 52. The slot and pin arrangement permitsboth sliding and pivotal movement of the slip 52 relative to the slipsleeve 58.'An extemallug 70 onthe slip sleeve 58 engages a downwardlyfacing shoulder 72 on the slip 52 to prevent pivoting of the slip 52while the assembly3 0. is being run into the well bore 34 and to=returnthe slip 52 to the position illustrated in FIG. 1 when retrieving theassembly from the well bore 34.

The slip 52 is a unitary member having a bore 74 extending therethroughthat intersects generally parallel end surfaces 76 and 78. The slip 52is re-bored or relieved providing enlargements 80 and 82 so that theslip 52 can be pivoted on the slip sleeve 58. A toothed, wall engagingportion 84 is located on the exterior of the slip 52 adjacent the endsurface 76 and a toothed, wall'engaging portion 86 is located on theexterior of the slip 52 adjacent the end surface 78. The teethillustrated on the portions 84 and 86 are arranged when in engagementwith the casing 32, to hold the assembly 30 against both upwardly anddownwardly directed forces. A leaf spring 88 is secured to the slip 52and has one end engaging the slip sleeve 58 to bias the slip 52 towardthe position illustrated in FIG. 1, that is, toward a retractedposition.

The-lower head 64 includes an upwardly facing shoulder or abutment 90that is engageable with the end surface 78 of the slip "52 for reasonswhich {will .be discussed more fully hereinafter. A shear screw 92 ismounted in the lower head 64 and extends into holding eng'a g'ement withthe body 36. The shear screw 92 retains the lower head 64 in theposition illustrated on the body 36 until patted; I I

OPERATION OF THE EMBODIMENT OF FIG. 1

The anchor assembly 30 is assembled as illustrated with the tubingstring 38 and lowered therewith into the well bore 34. The mating malethread 42 and female thread 44 on the upper head46j are engaged in theposition illustrated in FIG. I. Also as illustrated in FIG 1, the slipsleeve 58 is suspended between the upwardly facing shoulder 54 on theupper head 46 in the downwardly'fa'cing shoulder 62 on the lower head64. With the sleeve 58 thus positioned, thelug 70 thereon is inengagement with the shoulder 72 on the slip 52. Engagement between theshoulder 72 and the lug 70, will retain the slip 52 in the retractedpositionshown. Should the slip 52 move up wardly' on the slip sleeve 58,the leaf spring 88 will prevent pivoting of the slip 52 into the holdingposition. The slots 66 prevent engagement between the slip 52 andshoulder 50 even if the slip 52' does move upwardly.

Upon reaching the desired location in the well bore 34,

right-hand rotation isimparted to the tubing string 38. The bow springs48, which are in frictional engagement with the interior wall' of thecasing 32, prevent rotation of the upper head 46 so that relativerotation occurs between the male and female threads 42 and 44,respectively. Due to the relative rotation, linear motion, in a downwarddirection, is imparted to theupper head 46, moving the shoulder 50toward the end surface 76 of the slip 52i- The downward movement of theupper head 46 is relative to the slip sleeve 58 alsountil the abutment56 on the slip sleeve engages the downwardly facing shoulder 53 in theupper head 46. Upon such engagement, the slip sleeve 58 is carrieddownwardly, moving the lugs 70 relatively downwardly with respect to theslip 52 .to the position illustrated in FIG. 2. When thelug 70 movesaway from the shoulder 72, the slip 52 is in a position to be pivotedrelative to the slip sleeve 58.

Continued downward movement of the upper head 46 as a result ofthe'relative rotation, brings the end surface 78 on the slip 52 intoengagement with the upwardly facing shoulder or abutment 90 on the lowerhead 64 and also brings the downwardly facing shoulder or abutment 50 onthe upper head 46 into engagement with the surface 76 on the slip 52.The engagement between either or both of the surfaces 76 and 78 withtherespective abutment 50 and abutment 90pivots the slip 52 about thepins68 into the position illustrated in FIG. 2.

Asshown therein, the slip 52 is pivoted into the holding position, thatis into the position wherein the toothed, wall engaging portions 84' and86. are in holding engagement with the interior wall of the casing 32.Since the lateral distance between the surfaces 84 and 86 is greaterthan the interior diameterof the casing 32, the slip 52 is securelylocked to the casing 32 and, even though either or both of the abutments50 or 90 may be moved away fromthe slip, the slip 52 will remain set asshown.

Disengagement of the slip 52 and retrieval of the anchor as-" sembl'y'30is accomplished by imparting a relatively opposite. rotation to thetubing string 38 whereby the upper head 46' moves upwardly relative tothe mandrel 36 and slip sleeve 58.

When the abutment 56 again engages the upwardly facing surface 54 in theupper head 46, the slip sleeve 58 will be pulled upwardly therewith.

Continued upward movement of the upper head 46 and the v created thatwill disengage the portions 84 and 86 from the interior wall of thecasing 32. Once the disengagement between the portions 84 and 86 withthe casing 32 has been initiated, the spring 88 will bias the slip 52into the retracted position.

In the event that rotation cannot be imparted into the tubing string 38,relative rotation between the body 36 and upper head 46 cannot beattained, or the slip 52 cannot be released by rotation, the anchorassembly 30 can be retrieved by exerting an upward pull on the tubingstring 38 sufficient to shear the screw 92 carried in the lower head64.-When this occurs, the upward force on the tubing string 38 istransmitted through the body 36 and through the mating threads 42 and 44into the upper head 46. The upward force can then raise the upper head46 relative to the set slips 52.

As the upward movement of the upper head 46 continues, the abutment 56on the slip sleeve 53 engages the upwardly facing surface 54 on theupper head 46, pulling the lug 70 into engagement with the shoulder 72in the slip 52 and returning the slip 52 to the retracted position. Thelower head 64 is retrieved due to the engagement of the abutment 60 onthe lower end of the slip sleeve 58 with the downwardly facing surface62 in the lower head 64.

DESCRIPTION OF THE SLIP OF FIG. 4

FIGS. 4, 5, 6 and 7 illustrate another form of a slip constructed inaccordance with the invention and generally designated by the referencecharacter 100. The slip 100 could be utilized on the anchor assembly 30in lieu of the slip 52. As shown therein, the slip 100 comprises aunitary body 102, having an opening 104 extending therethrough.

As is shown most clearly in FIG. 5, the opening 104 is formed by a firstcylindrical bore 106 that extends along an axis 108. To permit the slip100 to pivot on a well tool (not shown), and as previously described inconnection with the slip 52 of FIG. 1, a second bore 110 extends throughthe body 102 along an axis 112 that is disposed atan angle relative tothe axis 108. The intersecting bores 106 and 1110 provide enlargementsin the opening 104 whereby the slip 100 can pivot when mounted on a welltool.

The body 102 includes an upper end 114 and a lower end 116fThe upper andlower ends 114 and 116, respectively, are intersected by both bores 106and 110. It will be noted that ends 114 and 116 are disposedsubstantially perpendicularly with respect to the axis 108 of the bore106. Thus, the end 114 is generally parallel to the end 116.

The body 102 is provided with an arcuate wall engaging portion 120located adjacent the end 114 and an arcuate wall engaging portion 122located adjacent the end 116. The wall engaging portion 120 isprovided'with downwardly oriented teeth 124 while the wall engagingportion 122 is provided with upwardly oriented teeth 12 6. Thus, whenthe slip 100 is in engagement with a well casing (not shown) or the wallof a well bore (not shown) the teeth 126 will aid in preventing movementof the slip upwardly therein and the teeth 124 will aid in preventingmovement downwardly therein.

The body 102 is constructed so that the dimension 128 between the wallengaging portion 120 and 122 as measured along a line that is generallyperpendicular to the surfaces will be greater than the diameter of theconduit (not shown) or well bore (not shown) in which the slip is run.That is, if the slip 100 is mounted on a well tool with the axis 108aligned with the longitudinal axis of the tool, the distance 123 will begreater than the diameter of the conduit or well bore in which the toolis run. When the slip 100 is in engagement with the conduit. it is inthe holding position.

The body 102 is also constructed to include a dimension 130 that ismeasured substantially perpendicular to the axis 112 and will be lessthan the interior diameter of the conduit or well bore in which the slip100 is run to permit movement of the slip therethrough. Stated inanother way, when the axis 112 is aligned with the longitudinal axis ofthe well tool (not shown) on which the slip 100 is mounted, the wallengaging portion and 122 will not engage the conduit or well bore wallsince the dimension is less than the internal diameter thereof. When theslip 100 is not in engagement with the conduit, it is in the retractedposition.

Threaded holes 132 and 1341, which are located in axial alignment,extend through the wall of the body 102 in a direction substantiallyperpendicular to the axes 100 and 112. The holes 132 and 134 are eacharranged to receive a threaded pin (not shown) that will engage the welltool on which the slip 100 is mounted to permit pivotal movement of theslip 100 between the holding and retracted positions. Thus, the centerline of the holes 132 and 134i define a pivot axis for the slip 100.

Intermediate the ends 114 and 116 there is provided on the body 102 adownwardly facing shoulder 138. The shoulder 138 is offset from thepivot axis 136 of the slip 100 in a direction so that engagement of theshoulder 138 with a portion of the well tool (not shown) pivots the slip100 into the retracted position wherein the axis 112 of the slip 100 isaligned with the longitudinal axis of the tool.

In a substantially diametrically opposed position on the body 102relative to the shoulder 138, a recess 140 is formed in the body 102 toreceive one end of a leaf spring, such as the leaf spring 88 illustratedin FIG. 1. The threaded opening M2, extending from the recess 140 intothe opening 104, is provided to receive a threaded fastener (not shown)for attachment of the leaf spring (not shown) to the body 102.

DESCRIPTION OF THE EMBODIMENT OF FIGURES 8A AND 83 FIGS. 8A and 8B,taken together, illustrate a mechanicallyactuated packer assemblygenerally designated by the reference character 200. Extending throughthe packer assembly 200 is a hollow body or mandrel 202.

The mandrel 202 includes a thread 204 at the upper end that is adaptedto be connected with a tubing string (not shown) for extending thepacker assembly 200 into the conduit 201 (see FIG. 10A). At its lower.end, the mandrel 202 screw provided with a thread 206 that is arrangedfor connecting the packer assembly 200 with apparatus in the welltherebelow.

Near the lower end of the mandrel 202 and on the exterior thereof thereis formed a J-slot 208. The J-slot 208 can be seen more clearly in thelayout view of FIG. 9. The .I-slot 203 is constructed to receive a shearscrew or pin 210 that is carried by a drag block assembly 212.

As shown in FIG. 8B, the drag block assembly 212 includes a drag blockbody 214 that slidably encircles the lower portion of the mandrel 202.Disposed within recesses in the drag block body 214 are a plurality ofdrag blocks 216 that are urged outwardly by a plurality of springs 218.The drag blocks 216 are provided to frictionally engage the interiorwall of the well bore or conduit 201 in which the packer assembly 200 isrun.

At its upper end, the drag block body 214 includes an annular recess220, providing an upwardly facing shoulder 222 and a downwardly facingshoulder 224. An upwardly facing abutment 226 on the upper end of thedrag block body 214 above the annular recess 220 is arranged to engage alower slip 228.

The lower slip 228 has a bore 230 extending therethrough that isconstructed as was the bore 104 of the slip 100 (see FIG. 5). The bore230 extends through the slip 220 intersecting a lower end 232 and anupper end 230. As clearly shown in FIG. 8B, the lower end 232 and upperend 234 he in planes disposed at an angle relative to each other. Thelower end 232 includes portions 235 that are offset from thelongitudinal axis of the packer assembly 200 for reasons that willbecome apparent hereinafter.

On its exterior, the slip 228 is provided with a lower gripping surface236 disposed adjacent the lower end 232 and upper gripping surface 238disposed adjacent the upper end 234. The surfaces 236 and 238 each havedownwardly oriented teeth formed thereon.

A leaf spring 240 is attached to the exterior of the slip 228 andfunctions to bias the slip 228 toward the retracted position asillustrated in F 1G. 88. Also, as described in connection with the slip100, the slip 228 includes a pair of pivot pins 242 forming a pivot axisfor the slip 228 that is disposed substantially perpendicular to thelongitudinal axis of the packer assembly 200. The pivot pins 242 arereceived in slots 244 shown by a dash line in FIG. 1. The slots 244 areformed in a lower slip sleeve 246.

The lower slip sleeve 246 extends through the slip 228 and has anannular abutment 248 on its lower end that is engageable with thedownwardly facing shoulder 226 in the upper end of the drag block body214. The lower end of the lower slip sleeve 246 is also in engagementwith a corrugated annular spring 250.

The corrugated spring 250 also engages the upwardly facing shoulder 222in the drag block body 214 biasing the slip sleeve 246 upwardly. Sincehe slip 228 is connected to the slip sleeve 246 by pivot pins 242, theslip 228 is also biased upwardly. Thus, the lower end 232 of the slip228 is held out of engagement with the annular abutment 226 on the upperend of the drag block body 214. With the end 232 out of engagement withthe abutment 226, the slip 228 can pivot much more readily toward theholding position as shown in FIG. 108.

An annular flange 252 encircles the upper end of the lower slip sleeve246. The flange 252 is engageable with an interior flange 254 carried bya packer compression sleeve 256 that slidingly encircles a packing shell253. Both the sleeve 256 and shell 258 are slidable on the mandrel 202.

A plurality of deformable packing elements 260 encircle the packingshell 258. While a plurality of elements 260 are illustrated, it will beunderstood that a single packing element or other suitable arrangementcan be used if desired. The lower end of the lowermost packing element260 is in engagement with the upper end of the compression sleeve 256.

As clearly shown in F108. 8A and 8B, the packing shell 258 is spacedradially from the mandrel 202 thereby forming a passageway 261 thatextends upwardly through the packer assembly 200. A plurality of ports262 are formed in the compression sleeve 256 below the packing elements260 and a plurality of ports 264 are formed in the packing shell 258above the packing elements 260. Thus, a bypass passageway that includesthe ports 262 the passageway 260 and the ports 264 is formed in thepacker assembly 200.

The packing shell 258 has a shoulder 266 engaging the upper end of theuppermost packing element 260 whereby telescoping movement between thecompression sleeve 256 and the packing shell 258 deforms the packingelements 260 relatively outwardly into sealing engagement with theinterior wall of the conduit 201 (see FIG. 10A).

The packing shell 258 also includes an interior shoulder 268 that isarranged to engage a valve retainer 270 carried by the mandrel 202. Whenthe retainer 270 engages the shoulder 268, telescoping of the sleeve 256and shell 258 can be accomplished to deform the packing elements 260. Aninterior flange 272 on the packing shell 258 is arranged to engage anannular flange 274 on the mandrel 202 to limit the upward travel of themandrel 202 relative to the shell 258.

Disposed between the flange 274 on the mandrel 202 and the valveretainer 270 is a resilient valve element 276. The resilient valveelement 276 is sized to enter the interior of the packing shell 258 andform a seal therewith to close the passageway 261 and, thus, to closethe bypass passageway in the assembly 200.

An upwardly facing shoulder or abutment 278 formed on the upper end ofthe packing shell 258 is arranged to engage an upper slip 280. The upperslip 280 is constructed substantially identically to the lower slip 228.The slip 280 is inverted, relative to the lower slip 228, on the packerassembly 200.1t will be noted however, that only one leaf spring 240 isprovided on the slip 280 instead oftwo as shown on the lower slip 228.

The upper slip 280 has a lower end 282 arranged to engage the abutment278 on the packing shell 258 and has a toothed, gripping surface 283adjacent to the end 282. An upper end 284 on the upper slip 280 isdisposed in a plane located at an angle relative to the lower end 282. Atoothed, gripping surface 285 is provided adjacent the end 284. Theteeth on the surfaces 283 and 285 are oriented in an upward direction.Surfaces 287, which are located on the upper end 284 of the slip 280,are offset from the longitudinal axis of the packer assembly 200 forreasons that will become apparent hereinafter.

The upper slip 280 has a downwardly facing shoulder 286 thereon locatedintermediate the upper and lower ends 282 and 284. The shoulder 286 ispositioned, relative to pivot pins 288 carried by the upper slip 280, sothat engagement between the shoulder 286 and a lug 290 that is locatedon an upper slip sleeve 292 will result in rotation of the upper slip280 into the retracted position shown in FIG. 8A.

The upper slip sleeve 292 includes a pair of slots 294 shown by a dashline that are arranged to receive the pivot pins 288. The upper end ofthe upper slip sleeve 292 includes an annular flange 2% that isengageable with a spring housing 298 carried by the mandrel 202.

A coil spring 300 disposed within the spring housing 298 has one end inengagement with the mandrel 202 and the opposite end in engagement withthe flange 296 on the upper slip sleeve 292. The spring housing 298 hasa lower end 302 that is engageable with the upper end 284 of the slip280 for purposes that will be described more fully hereinafter.

OPERATION OF THE EMBODlMENT OF FIGURES 8A AND 88 FIGS. 8A and 8Billustrate the position of the various components of the packer assembly200 as the packer assembly is being lowered into the conduit 201.

As shown in FlGS. 8B and 9, the pin 210 is disposed in the upper end ofthe lower portion of the .l-slot 208. With the pin 210 in this position,the drag block assembly 212 cannot move upwardly relative to the mandrel202 even though the drag blocks 216 are in frictional engagement withthe interior wall of the conduit 201.

With the drag block assembly 212 retained on the mandrel 202, thedownwardly facing shoulder 224 in the drag block assembly 212 engagesthe abutment 248 on the lower end of the lower slip sleeve 246, pullingthe lower slip sleeve 246 downwardly therewith. The annular flange 252on the upper end of the lower slip sleeve 246 is in engagement with theinterior flange 254 on the packer compression sleeve 256, pulling thepacker compression sleeve 256 therewith into the conduit 201. The upperend of the compression sleeve 256 and the lower end of the packing shell258 are in engagement as shown in FIG. 8B and, thus, the packing shell258 and the packing elements 260 are also pulled into the conduit 201.

The lower slip 228 is retained in the retracted position illustratedunder the urging of the leaf springs 240. Therefore, even though thelower slip 228 may ride upwardly in the slots 244, the lower slip 228cannot move into holding position and, thus, cannot engage the interiorwall of the conduit 201 during the running of the packer assembly 200into the well bore.

It should also be noted that as the packer assembly 200 is lowered intothe well bore, the bypass valve element 276 is in its upper position,that is, it is in a position wherein the passageway 261 is open topermit fluid to bypass the packing elements 260 by flowing from theports 262 through the passageway 261 and outwardly through the ports264.

At the upper end of the packer assembly 200, the coil spring 300 urgesthe upper slip sleeve 292 relatively downwardly holding the annularflange 296 thereon in engagement with the lower end of the springhousing 298 and, thus, holding the upper slip 280 in a position out ofengagement with the lower end 302 of the spring housing 200. The lug 290on the upper slip sleeve 292 engages the downwardly facing shoulder 286on the upper slip 280 to prevent engagement between the lower end 282 ofthe upper slip 280 and the upwardly facing shoulder 278 on the packingshell 258. Should the upper slip 280 ride upwardly due to fluidresistance, the leaf spring 240 retains the upper slip 280 in theretracted position as illustrated in FIG. 8A. Thus, the upper slip 280cannot engage the wall of the well bore as the packer assembly 200 islowered therein.

Upon reaching the desired location in the well bore for setting thepacker assembly 200, the mandrel 202 is raised slightly by pullingupwardly on the tubing string (not shown). The upward movement of themandrel 202 places the shear pin 210 in the position 210a as shown inFIG. 9, since the drag block assembly 212 is retained in a stationaryposition by the frictional engagement of the drag blocks 216 with theinterior wall of the conduit 201.

The mandrel 202 is then rotated in the appropriate direction andsimultaneously lowered to move the pin 210 from the position 210a to theposition 21%. As the mandrel 202 moves downwardly, the bypass valveelement 276 moves into the passageway 261 forming a seal with thepacking shell 258, closing the passageway 261. When the valve retainer270 engages the interior shoulder 268 in the packing shell 258, downwardmovement is also imparted to the packing shell 258.

Continued downward movement of the mandrel 202 and the packing shell 258forces the packer compression sleeve 256 downwardly relative to thelower slip sleeve 246 and lower slip 228. The sleeve 246 and lower slip228 are retained in a relatively fixed position by the drag blockassembly 212. The downward movement of the packer compression sleeve 256continues until the flange 254 thereon engages the upper end 234 of thelower slip 228 as illustrated in FIG. 103. The engagement between theflange 254 and the upper end 234 pivots the lower slip 228 into theholding position wherein the gripping surfaces 236 and 238 on the lowerslip 228 are in firm engagement with the interior wall of the conduit20]. When this occurs, further downward movement of the packercompression sleeve 256 is prohibited.

Continued downward movement of the mandrel 202 carries the packing shell258 downwardly therewith in telescoping relationship to the packercompression sleeve 256. As the telescoping movement between the packercompression sleeve 256 and the packing shell 258 occurs, the packingelements 260 are deformed outwardly into sealing engagement with theconduit 201 as illustrated in FIG. 10A.

Simultaneously with the foregoing, the mandrel 202 through the coilspring 300 has moved the upper slip sleeve 292 downwardly so that thelug 290 is out of engagement with the shoulder 286 on the upper slip280. Also, the relative downward movement of the upper slip sleeve 292relative to the upper slip 280 has moved the slots 294 to a positionwherein the upper end thereof engages the pivot pins 288 to carry theupper slip 280 downwardly forcing the lower end 282 into engagement withthe abutment 278 on the packing shell 258.

The engagement between the lower end 282 of the upper slip 280 and theabutment 278 pivots the upper slip 280 into the holding positionillustrated in FIG. 10A. As shown therein. the grippingsurfaces 283 and285 are in firm holding engagement with the conduit 201. As described,the packer assembly 200 is in the set position with the upper and lowerslips 280 and 228, respectively, in holding engagement with the conduit201 and with the packing elements 260 deformed into and retained insealing engagement with the conduit 201 During the operation of settingthe packer assembly 200 by compression, that is, by setting weightthereon as previously described, the upper slips 280 are moved intoholding engagement with the conduit 201 during deformation of thepacking elements 260. To assure that the desired deformation of thepacking elements 260 is attained, the upper slip 280 is provided withthe surfaces 287. As may be seen in FIG. 10A, the surfaces 287 on theupper slip 280 are displaced to the right of the longitudinal axis ofthe packer assembly 200 and. of

course, to the right of the pivot axis formed by the pivot pins 288.Thus, the lower end 302 of the spring housing 298 will engage thesurfaces 287 if sufficient weight is exerted to compress the coil spring300.

When such engagement occurs, a moment is created tending to rotate theupper slip 280 toward the retracted position. Therefore, it can beappreciated that application of additional weight to provide moredeformation of the packing elements 260 will rotate the upper slip 280toward the position illustrated in FIG. 11 due to the engagement betweenthe surfaces 287 and the lower end 302 of the spring housing 298. In theposition shown, the upper slip 280 can slide downwardly within theconduit 201, permitting the direct application of the weight through themandrel 202 and the packing shell 258 to the packing elements 260.

Sometimes, the packer assembly 200 will be utilized in wells whereinsufficient tubing weight is not available to set the packer assembly 200by applying weight thereto, that is, insufficient weight is available toset the packer assembly 200 in compression. When such a condition isencountered, the packer assembly 200 is first set in compression, aspreviously described attaining a holding engagement between the upperand lower slips 280 and 228 and the conduit 201. After this point in thesetting of the packer assembly 200 has bee attained, the mandrel 202 israised, moving the pin 210 into the position 210c as shown in FIG. 9.

As the mandrel 202 is raised, the compressive force exerted on the coilspring 300 is reduced. However, the energy stored therein, retains theupper slip sleeve 292 in the position illustrated in FIG. 10A with thelug 290 thereon spaced from the downwardly facing shoulder 286 on theupper slip 280.

The upward force, transmitted from the mandrel 202 into the pin 210,carries the drag block assembly 212 upwardly and the abutment 226 on theupper end of the drag block assembly 212 engages the surfaces 235 on thelower end 232 of the lower slip 228. The engagement between the abutment226 and the surfaces 235 results in a moment being exerted on the lowerslip 228 tending to rotate the lower slip 228 toward the retractedposition as previously described in connection with the downwardmovement of the upper slip 280 and as shown in FIG. 11.

As a result of the movement of the lower slip 228 toward the retractedposition, the lower slip 228 is disengaged from the conduit 201 and canmove upwardly with the mandrel 202 and drag block assembly 212. Asclearly shown in FIG. 1013, the upper end 234 of the lower slip 228 isin engagement with the flange 254 of the packer compression sleeve 256,forcing the packer compression sleeve 256 upwardly relative to thepacking shell 258.

The abutment 278 on the upper end of the packing shell 258 is inengagement with the lower end 282 of the upper slip 280 and, thus, isprevented from moving upwardly. As a result, a telescoping movementoccurs between the packer compression sleeve 256 and the packing shell258 and the packing elements 260 are deformed into sealing engagementwith the conduit 201.

When the upward force is relieved on the mandrel 202, the lower slip228, through its engagement between the upper end 234 and the flange 254on the lower end of the packer compression sleeve 256, returns to theholding position, that is, into holding engagement with the conduit 201.Thus, the upper slip 280 and the lower slip 228 are in firm holdingengagement with the conduit 201, retaining the packing elements 260deformed into sealing engagement with the conduit 201.

When it is desired to retrieve the packer assembly 200 from the wellbore, the tubing string (not shown) and the attached mandrel 202 arerotated in the relatively opposite direction and raised so that the pin210 returns to the position 2100 as shown in FIG. 9. As the mandrel 202moves upwardly, the annular flange 274 thereon engages the interiorflange 272 on the packing shell 258. The engagement between the annularflange 274 and. interior flange 272 raises the packing shell 258 torelieve the compressive load on the packing elements 260.

As upward movement continues, the lower end of the packing shell 258engages the upper end of the packer compression sleeve 256, raising theflange 254 out of engagement with the upper end 234 of the lower slip228. When this occurs, the leaf springs 240 pivot the lower slip 228into the retracted position as illustrated in FIG. 88.

If the lower slip 228 is wedged into holding engagement with the conduit201 so thatthe leaf springs 240 cannot return the lower slip 228 to theretracted position, the upwardly facing abutment 226 on the drag blockassembly 212 comes into engagement with the Surfaces 235cm the lowerslip 228 applying a moment thereto and aiding the leafsprings 240 inreturning the lower slip 228' to thesett'acted position. The bypassvalve element 276 has been pulled-out of the passageway 261, equalizingthe pressures above and below thepacking elements 260 prior to releasingthe slips 228 and 280.

Simultaneously with the foregoing, the annular flange 296 on the upperend of the upper slip sleeve 292 engages the lower end 302 of the springhousing 298. When this occurs, theupper slip sleeve 292 is pulledupwardly relative to the upper slip 280 bringing the lug 290 on theupper slip sleeve 292 into engagement with the downwardly facingshoulder 286, on the upper slip- 280.'When the lug 290 engages thedownwardly facing shoulder 286, a moment is applied to the upper slip280 pivoting the upper slip 280 into the retracted position asillustrated in FIG, 8A. Upon reachingthis position, the variouscomponents of the'pac'ker assembly 200 are in the retrieving positionwith the packing elements 260 returned substantially to the positionillustrated in FIG. 8A and with the upper and lower slips 280 and 228'in the retracted positions shown in FIGS. 8A and 8B. 1 v

If, for some reason, the packer'assembly '200becomes stuck and cannot beretrieved in the; normal fashion, an upward force of sufficientmagnitude exe'rted'on the mandrel 202 shears the pin 210 permittingthemandrel 202 to move upwardly relative to the drag block assembly 212.After shearing the pin 210, the packer can bereturned to the retrievingposition as previously described. i

EMBODIMENT OF FIGURES 12A AND 128 FIGS. 12A and 1213, taken. together;illustrate a two-slip anchor assembly generally designated by thereference character 304. The anchorassenibly 304 includes a mandrel 306that extends downwardly therethrough. The upper end of the mandrel 306is provided with a thread 308 arranged for connection with a tubingstring (not shown) used to move the anchor assembly 304 in a well boreor through the conduit 201 (see FIG. 13). The lower end of the mandrel306 includes a thread 310 for connecting the anchor assembly 304 toother apparatus disposedwithin the well bore below the anchor assembly.

Near its lower end portion and on the exterior thereof, the mandrel 306is provided with a .l-slot 312 that is constructed like the J-slot 208of FIG. 9. Near its medial portion, the mandrel 306 includes anoutwardly projecting flange 314. The purpose of the flange 314 willbecome more evident as the description proceeds.

The .l-slot 312 isarranged to receive a shear screw or pin 316 that ismounted in a drag spring assembly 318. The drag spring assembly 318includes a drag spring body 320 having a plurality of resilient dragsprings 322 arranged on the exterior thereof. The drag springs 322frictionally engage the conduit 201.

The drag spring body 320 includes an upper end or abutment 324 and hasan annular recess in the upper end forming a downwardly facing shoulder326 and an upwardly facing shoulder 328. A corrugated spring 330 islocated in the annular recess in engagement with the upwardly facingshoulder 328. An annular flange 332 located on the lower end of a lowerslip sleeve 334 is disposed inthe annular recess and in engagement withthe downwardly facing shoulder 326.

i The lower slip sleeve 334 extends upwardly through a bore 336 of alower slip 338. The lower slip sleeve 334 slidingly encircles themandrel 306 and has an annular flange 340 on the upper end thereof.

The bore 3360f the lower slip 338 is constructed in the same manner aswas the bore or opening 104 in the slip shown in FIG. 5.

The lower slip 338 includes a lower end 342 and an upper end 344. Asshown in FIG. 128, the upper and lower ends 344 and 342, respectively,are located in angularly disposed planes. The lower end 342 includessurfaces 345 for purposes that will become evident hereinafter.

Adjacent the upper end 344 of the slip 338 there is provided a toothedwall gripping portion 346. The teeth on the gripping portion 346 areoriented in a downward direction to prevent movement of the anchorassembly 304 downwardly when disposed in the conduit 201. The lower slip338 carries leaf springs 348 that engage the exterior of the lower slipsleeve 334 to bias the lower slip 338 toward the retracted position asshown in FIG. 12B. A lower slip 338 also includes a second wall engagingportion 350 located adjacent the lower end 342. The wall engagingportion 350 does not include teeth. It has been found that a slipconstructed in accordance with the invention will hold without teeth,but the teeth on one portion assures an adequate holding force withoutslipping.

Pivot pins 352 carried by the lower slip 338 extend into slots 354 thatare located in the lower slip sleeve 334. As previously mentioned, theflange'332 on the lower slip sleeve 334 engages the spring 330, so thatthe spring 330 holds the lower end 342 out of engagement with theabutment 329 to permit the lower slip 338 to pivot more easily towardthe holding position.

The. annular flange 340 on the upper end of the lower slip sleeve'334 isengageable with a flange 356 formed on the lower end of an upper headassembly358, that is, on a head assembly body 359. A downwardly facingabutment 360 on the lower end of the. head assembly body 359 is arrangedto engage the upper end 344 of the lower slip 338. Near its intermediateportion, the head assembly body 359 is provided with an interior flange362. that is engageable with the flange 314 carried by the mandrel 306for purposes that will become more apparent hereinafter. An upperinterior flange 364 on the head assembly body 359 is also engageablewith the flange 314 on the mandrel 306 to prevent engagement of the shutment 360 with the lower slip 338 as the anchor assembly 304 is beinglowered into the well bore.

A plurality of retainer screws 366, which are secured in the headassembly body 359, extend through apertures 368 in a movable head member370 that encircles the upper end of the body 359. The aperture andretainer screw arrangement permits the movable head member 370 to moveaxially to a limited extent with respect to the head assembly body 359.

Positioned within the head member 370 are a plurality of segments 372that slidingly encircle the mandrel 306. A garter spring 374 retains thesegments 372 resiliently on the mandrel 306.

Each of the segments 372 includes a downwardly facing tapered surface376 that is engageable with a mating upwardly facing tapered surface 378on the body 359. Similarly, each of the segments includes an upwardlyfacing tapered surface 380 that mates with a downwardly facing taperedsurface 382 on the interior of the upper head member 370. The upper headmember 370 includes an upwardly facing abutment 38 that is engageablewith a lower end 386 on an upper slip 388.

The upper slip 388 includes a toothed. wall engaging portion 390adjacent the lower end 386 and a smooth wall engaging portion 392adjacent an upper end 394. The teeth on the portion 392 are oriented inan upward direction to prevent up ward. movement of the anchor assembly304 when the upper slip 388 is in the holding position.

The upper slip 388' also has a bore 396 extending 'therethrough slidablyand pivotally positioning the upper slip 388 on an upper slip sleeve398. A downwardly facing shoulder 400 on the upper slip 388 isengageable with a lug 402 carried by the upper slip sleeve 398. Pivotpins 404cm- 13 ried by the upper slip 388 exr'ern into slots 406 formedin the upper slip sleeve 398 to pivotally support-the upper slip 388 onthe anchor assembly 304.

The upper slip sleeve 398, in addition to the lug 402, includes anelongated lower end portion 408 that is adapted to extend into themovable head member 370 and into engagement with the segments 372 forpurposes that will be explained more fully hereinafter. At its upperend, the upper slip sleeve 398 includes a flange 410 that is engageablewith the lower end 412 of a spring housing 414; Y

The springhousing 414 is connected to a forms a part of the mandrel 306.A coil spring 416 is disposed within the spring housing 414. The lowerend of the coil spring 416 is in engagement with the flange 410 on theupper' slip sleeve 398 and the upper end of the coil spring 416 is inengagement with the upper end of s the spring housing 414 therebyexerting a downwardly directed force on the upper slip sleeve 398.

EMBODIMENT OF FIGURES 12A AND 12B OPERATION or THE [connected by thethread 308 to a tubing string (not shown).

The various components of the anchor assembly 304 will be in thepositions illustrated in FIG. 12A and 1213 as the anchor assembly 304 isrun into the conduit 201.

As shown therein, the upper slip 388 is retained in the retractedposition by the engagement of the downwardly facing shoulder 400 withthe lug 402 on the upper slip sleeve 398. The leaf spring 348 alsobiases the upper slip 388 toward the retracted position as illustrated.The head assembly 358 cannot move upwardly into engagement with theupper slip 388 due to the engagement of the flange. 340 on the lowerslip sleeve 334 with the flange 356 on the head assembly body 359.

The lower slip-sleeve 334 is prevented from moving upwardly due to theengagement of the flange 332 on the lower end thereof with thedownwardly. facing shoulder 326 in the drag spring body 320. As clearlyillustrated in FIG. 128, the shear pin 3l6is disposed in the J-slot 312in engagement with the mandrel 306 thereby preventing the drag springassembly 318 from moving upwardly. Thus, all the components of theanchor assembly 304 are locked in the positions illustrated in FIGS. 12Aand 128 as the anchor assembly 304 is lowered into the conduit 201. A

Upon reaching the desired location in the well bore for setting theanchor assembly 304, rotation is imparted to the tubing string (notshown) and to the connected mandrel 306 while raising and then loweringthe mandrel 306 so that the shear pin 316 moves through the elongatedportion of the .1- slot 312 as was described in connection with theJ-slot and pin arrangement shown in the layout of FlG.-9.

As the mandrel 306 is lowered relative to the drag spring assembly 318,which is retained in a relatively-fixed position due to the frictionalengagement between the drag springs 322 and the interior wall of theconduit 201, the flange 314 on the mandrel 306 engages the interiorflange 362'in the upper head assembly 358. The engagement therebetweenmoves the head assembly 358 downwardly until the lower abutment 360thereon engages the upper end 344 of the lower slip 338. When thisengagement occurs, the lower slip 338 is rotated or pivoted about thepins 352 into the holding position, that is, into the position whereinthe toothed, gripping surface 346 is firmly engaged with the interiorwall of the conduit 201.

When the lower slip 338 is disposed in the holding position, downwardmovement of the head assembly 358 is no longer possible. At this time orsimultaneouslywith a portion of the foregoing, the upper slip sleeve 398is moved downwardly relative to the upper head assembly 358 andthe lowerend 408 thereof enters the movable head member 370. As the lower end 408enters the movable head 370, it engages the segments 372, moving thesegments 372 radially outwardly against the force of the spring 374. Asthe segments 372 move outwardly, the tapered surfaces 376 and 380thereon engage the mating tapered surfaces 378 and 382 locking themovable head member 370 in the position illustrated in FIG. 13.

Simultaneously, the lug 402 on the upper slip sleeve 398 has moved awayfrom the downwardly facing shoulder 400 in the upper slip 388. The upperslip 388 is also carried downwardly due to the engagement of the pins404, with the upper slip sleeve 398 at the top end of the slots 406. Thedownward movement of the upper slip 388 brings the lower surface 386thereon into engagement with the abutment 384 on the head member 370 androtates or pivots the upper slip 388 into the holding position asillustrated in H6. '13. Thus, the lower slip 338 is disposed in firmholding engagement with the conduit 201 and the upper slip 388 is lockedinto holding engagement with the conduit 201. The arrangement of the.teeth on the slips 338 and 388 prevent movement of the anchor assembly304 in either the upward or downward direction in the conduit 201.

When it is desired to retrieve the anchor assembly 304 from the wellbore, rotation, in the opposite direction, is imparted to the mandrel306 while simultaneously raising the mandrel 306 to return the pin 316to the lower portion of the J-slot 312. As the mandrel 306 is raised,the lower end 412 on the spring housing 414 again engages the flange 410on the upper slip sleeve 398, pulling the upper slip sleeve 398 upwardlytherewith. As the upper slip sleeve 398 moves upwardly, the lower end408 thereon moves-out from under the segments 372, permitting the spring374 to return the segments 372 to position illustrated in FIG. 12A. Whenthis occurs, the movable head member 370 is free to move downwardlyrelative to the retaining screws 366, thus moving the abutment 384 awayfrom the lower end 386 of the upper slip 388.

While the movable head arrangement has been described in connection withthe anchor assembly 304, it will be apparent that the arrangement can beused with any of the anchors and packers described herein. The mainpurpose of the arrangement is to reduce the force required to return theengaged slip to the retracted position.

if the upper slip 388 is not wedged too tightly in the conduit 201, theleaf spring 348 will return the upper slip 388 to the retracted positionas illustrated in FIG. 12A. if the upper slip 388 is wedged tightly intothe conduit 201, the movement of the upper slip 388 to the retractedposition may not occur until lug 402 on the upper slip sleeve 398engages the downwardly facing should 400 in the upper slip 388. Uponengagement between the lug 402 andthe shoulder 400, a moment is impartedto the upper slip 388 that will positively disengage the upper slip 388from the conduit 201 and return it to the retracted position.

The flange 314 on the mandrel 306 is also moved upwardly until itengages the flange 364 on the upper end of the upper head assembly 358.When this occurs, the upper head body 359 is moved upwardly moving thelower abutment 360 thereon out of engagement with the upper end 344 ofthe lower slip 338. The lower slip 338 is then free to pivot under theurging of the springs 348 into the retracted position as illustrated inFIG. 12B.

To be certain that the lower slip 338 does return to the retractedposition, the lower flange'356 in the upper head body 358 engages theflange 340 on the lower slip sleeve 334, carrying the lower slip sleeve334 upwardly therewith. As previously described, the flange 332 on thelower end of the lower slip sleeve 334 is in engagement with the dragspring body 320 so that the drag spring 320 is carried upwardlytherewith. If the lower slip 338 has not returned to the retractedposition, the abutment 324 on the upper end of the drag spring body 320engages the surfaces 345 on the lower slip 338 to create a moment on thelower slip 338, rotating it about the pivot pins 352 into the retractedposition. Upon release of the lower slip 338 the anchor assembly 304 isreturned to the condition wherein it can be retrieved from the conduit2.01.

A safety release feature is built into the anchor assembly 304 as wasbuilt into the packer assembly 200. That is, the shear pin 316 will partif sufficient upward force is exerted on the mandrel 306, permitting therelative upward movement of the various components to occur even thoughproper rotation and release of the .I-slot and pin arrangement cannot beaccomplished. The anchor assembly 304 can be retrieved as previouslydescribed after the shear pin 316 has been parted.

DESCRIPTION OF THE EMBODIMENT OF FIGURES 15A,

15B, AND 15C FIGS. 15A, 15B, and 15C taken together comprise ahydraulically-actuated packer assembly that is generally designated bythe reference character 420. The packer assembly 420 includes a mandrel422 having a thread 424 at its upper end arranged for connection with atubing string (not shown) that is used to move the packer assembly 420through a well bore or conduit 201. The lower end of the packer assembly420 is threadedly connected with a valve nipple 425.

The valve nipple 425 has an annular valve seat 426 on the interiorthereof. The valve seat 426 is provided to sealingly receive a valveball 427 (see FIG. 16C) so that hydraulic pressure can be applied to thepacker assembly 420. The lower end of the landing nipple 425 is providedwith a thread 428 whereby other apparatus can be attached thereto belowthe packer assembly 420.

As shown in FIG. 15C, a shear screw or pin 430 connects a lower headassembly 432 with the mandrel 422. The lower head assembly 432 has anannular recess in the upper interior end thereof providing a downwardlyfacing shoulder 434 and an upwardly facing shoulder 436. A flange 438 onthe lower end of a lower slip sleeve 440 is disposed in the annularrecess in engagement with the downwardly facing shoulder 434. Acorrugated annular spring 442 is located in the annular recess betweenthe flange 438 and the upwardly facing shoulder 436 to bias the lowerslip sleeve 440 relatively upwardly.

The lower slip sleeve 440 extends upwardly from the lower head assembly432 through a bore 444 in a lower slip 446. A flange 448 on the upperend of the lower slip sleeve 440 is engageable with a lower end 450 of apiston 452. Slots 454 in the lower slip sleeve 440 are arranged toreceive pivot pins 456 carried by the lower slip 446 so that the lowerslip 446 is pivotally carried by the lower slip sleeve 440.

The bore 444 in the lower slip 446 is preferably constructed as is thebore 104 in the slip 100 previously discussed. The lower slip 446 has alower end 458 disposed adjacent, but in spaced relationship to the upperend of the lower head assembly 432. The spring 442 biases the lower slipsleeve 440 upwardly and the sleeve 440, through the pivot pins 456,holds the lower end 458 away from the head assembly 432.

Adjacent the lower end 458 of the lower slip 446, there is provided atoothed, wall gripping portion 460. The teeth on the portion 460 areoriented in a downward direction to prevent movement of the packerassembly 420 downwardly in the well bore when the lower slip 446 is inthe holding position.

A toothed, wall gripping portion 462 is disposed adjacent an upper end464 of the lower slip 446. The teeth on the portion 462 are alsooriented in a downward direction. A lower end 458 of the lower slip 446includes surfaces 466 that are offset from the pivot pins 456 forreasons that will be described more fully hereinafter.

Leaf springs 468 have one end secured to relatively opposite sides ofthe lower slip 446. The free ends of the springs 468 engage the lowerslip sleeve 440 to bias the lower slip 446 about the pivot pins 456toward the retracted position of the slip 446 as illustrated in FIG.15C.

As shown in FIG. 153, the piston 452 slidingly encircles the lower slipsleeve 440 and the mandrel 422 and a portion of the piston 452 extendsupwardly into a cylinder 470. As the packer assembly 420 is lowered intothe well bore, the piston 452 and cylinder 470 are prevented from movingrelative to each other by a shear screw or pin 472 that is carried bythe cylinder 470 and extends into the piston 452.

A split-ring retainer 474 having teeth on the interior thereof isdisposed between a downwardly fading tapered surface 476 in the cylinder470 and the piston 452. The retainer 474 is arranged to permit thepiston 452 to move downwardly relative to the cylinder 470 but to wedgebetween the cylinder 470 and piston 452 to prevent upward movement ofthe piston 452 relative to the cylinder 470.

The upper end of the piston 452 is provided with an external seal 478that slidingly and sealingly engages the cylinder 470 and an internalseal 480 that slidingly and sealingly engages the mandrel 422. A seal482 carried by the cylinder 470, relatively above the seals 478 and 480,slidinglyand sealingly engages the mandrel 422 forming a chamber 484therebetween. A pressure port 486 extends through the mandrel 422providing communication between the interior of the mandrel 422 and thechamber 484.

To prevent relative movement between the mandrel 422 and the cylinder470 as the packer assembly 420 is lowered into the well bore, aplurality of locking dogs 488 are located between the cylinder 470 andthe mandrel 422. A lower end 490 on each of the locking dogs 488 extendsinto a recess 492 formed in the exterior of the mandrel 422. A lug 494on each of the locking dogs 488 extends into a recess 496 formed in thecylinder 470. A garter spring encircles the dogs 488 resiliently biasingthe lower ends 490 thereon into the recess 492.

A projection 500 formed on the upper end of the piston 452 also engagesthe lower end 490 of the dogs 488 to hold the lower end 490 in therecess 492 during the lowering of the packer assembly 420 into the wellbore. Thus, the cylinder 470 is secured to the mandrel 422 and thepiston 452 is also secured to the mandrel 422 thereby preventingrelative move ment therebetween and preventing inadvertent setting ofthe packer assembly 420 as it is lowered into the well bore.

Referring to FIG. 15A, it can be seen that the upper end of the cylinder470 is in engagement with the lower most of a plurality of deformablepacking elements 502. While illustrated as a series of stacked packingelements 502 and spacers 504, any suitable form of deformable packingcan be utilized in the packer assembly 420. The packing elements 502 arecarried by a packing shell 506. The lower end of the shell 506 isslidably received in the upper end of the cylinder 470. A flange 508 onthe lower end of the packing shell 506 is engageable with the interiorof the upper end of the cylinder 470.

The packing shell 506 slidingly encircles the mandrel 422 and is spacedtherefrom to form a passageway 510. The passageway 510, ports 512 in thecylinder 470 and ports 514 in an upper head 516 form a bypass passagewayto permit fluid to flow by the packing elements 502 and through thepacker assembly 420 between the packing shell 506 and the mandrel 422.

The packing shell 506 is threadedly connected at its upper end with theupper head 516. The upper head 516 includes an abutment 517 that is inengagement with the topmost of the packing elements 502.

An interior flange 518 in the upper head 516 is arranged to engage apickup ring 520 carried by the mandrel 422.

The upper head 516 also carries a resilient bypass valve element 522that is engageable with the exterior of the mandrel 422 during settingof the packer assembly 420 to close and. thus, prevent fluid flowthrough the passageway 510. The upper head 516 also includes an upperend 524 that is engageable with a lower end 526 on an upper slip 528.

Adjacent the lower end 526 of the upper slip 528 there is provided atoothed, wall gripping portion 530. The teeth on the portion 530 areoriented in an upward direction to prevent upward movement of the packerassembly 420 in the well bore when the packer assembly 420 is settherein. Also, the upper slip 528 is provided with a wall grippingportion 532 located adjacent an upper end 534. The portion 532 has teeththereon that are also oriented in a upward direction to prevent movementof the packer assembly 420 upwardly.

carried by an upper slip sleeve 540. The lug 538, when in engagementwith the shoulder 536, prevents movement of the upper slip 528 from theretracted position into the holding position and functions to return theslip 528 to the retracted position from theholding position as will bedescribed.

The upper slip 528 is also provided with a leaf'spring 539. The spring539 engages an upper slip sleeve 540 to bias the upper slip 528 towardthe retracted position. Pivot pins 542, carried by the upper slip 528,are located in slots 544 located in the upper slip sleeve 540. Y

The upper end of the upper slip sleeve 540 includes a flange 546 thatis" disposed within a recovery "sleeve 548. The recovery sleeve 548 isattached to the mandrel 422 and is in engagement with the flange 546 onthe upper'slip sleeve 540 so that the upper slip sleeve 540 moves withthe mandrel 422.

OPERATION OF THE EMBODIMENT OF FIGURES A,

' 15B, AND 15c;

FIGS. 15A, 15B, and 15C, taken together, illustrate the variouscomponents of theipacker assembly 420 in the positions they occupyduring lowering of the packer assembly 420 into the well bore. The lowerhead assembly 432 is retained on the mandrel 422 by the shear pin 430.The lower slip sleeve 440 is pulled into the well-bore with the lowerhead assembly 432 due to the engagement between the lower flange 438 onthe lower slip sleeve 440 and the downwardly facing shoulder 434 in thelower head assembly 432.

While the lower slip 446 vcan move upwardlyon the lower slip sleeve 440,its upward movement is limited by the engagement of the pins 456 withthe lower slip sleeve 440 at the top end of the slots454. The leafsprings 468 on the lower slip 446 retain the lower slip 446 in theretracted position illustrated in FIG. 15C. 1

, The flange 448 on the upper end of the lower slip sleeve 440 is inengagement with the lower end 450 of the piston 452, carrying the piston452 into the well bore therewith. The shear pin 472 locks the piston 452and the cylinder 470 together so that the cylinder 470 is also pulledinto the well bore with the piston 452 and mandrel 422. The cylinder 470is locked against movement relative to the mandrel 422 by the lockingdogs 488 as previously described The upper end of the cylinder 470 is inengagement with the flange 508 on:the lower end of the packing shell 506thereby pulling the packing shell 506, the packing elements 502 and theattached upper head .516 into the well bore. The'upper slip .528 isprevented-from moving downwardly into engagement with the upperend 524of the upper head '516 by the engagement of the lug 538 on the upperslip sleeve 540 with the downwardly facing shoulder 536 in the upperslip 528. If fluid flow should cause the upper slip 528 to move upwardlyrelative to the upper slip sleeve 540, the spring 539 carried by theupper slip 528 prevents rotation of the upper slip 528 into the holdingposition.

The position of the upper slip sleeve 540 is fixed relative to themandrel 422 by the engagement of the recovery sleeve 548 with the flange546 on the upper end of the upper slip sleeve 540. As can be appreciatedfrom the foregoing, the various components of the packer assembly-420are securely retained in the unset or retracted position as the packeras sembly 420 is lowered into the well bore.

As the packer assembly 420 is lowered, the bypass valve element 522 isout of engagement with the mandrel 422 and the passageway 510 is'open.Fluid in the well bore can pass upwardly, entering the ports 512,flowing through the passageway 510 between the mandrel 422 and packingshell 506, and outwardly through the ports 514; The fluid thus bypassesthe packing elements 502, permitting the packer assembly 420 to belowered at a higher rate of speed and reducing the possibility ofwashing one or more of the packing elements 502 off the packer assembly420.

Upon reaching setting depth in the well bore, the valve ball 427 orother suitableclosing device is dropped into the tubing string (notshown). The valve ball 427 passes downwardly through the tubing stringand mandrel 422 until it lands on the annular valve seat 426 in thevalve nipple 425.

When the valve ball 427 lands on the seat 426, the interior of themandrel 422 is closed and fluid pressure can be applied to the packerassembly 420. The pressure in the mandrel 422 is exerted through thepressure ports 486 in the mandrel 422 into the chamber 484 formed by thepiston 452, mandrel 422 and cylinder 470. As the pressure builds up inthe chamber 484, a force is applied to the piston 452 and to thecylinder 470. When the applied force reaches a sufficiently highmagnitude, the shear pin 472 parts, as illustrated in F lGS. 16B and16C, permitting the piston 452 to move downwardly.

' The locking dogs 488, which are located in the recess 492 in themandrel 422, prevent upward movement of the cylinder 470. When thepiston 452 moves downwardly, the locking dogs 488 are free to move outof the recess 492. The cylinder 470 then moves upwardly forcing thelocking dogs 488 out of the recess 492.

As the piston 452 moves downwardly, the lower end 450 thereon engagesthe upper end 464 of the lower slip 446, pivoting the lower slip 446into the holding position illustrated in FIG. 16C. When the slip. 446reaches the holding position, the teeth on the gripping portions 460 and462 securely engage the interior of the conduit 20,1, preventingdownward movement of the lower slip 446 and piston 452.

With the lower slip thus fixed relative to the conduit 201, the pressurein the chamber 484 drives the cylinder 470 upwardly until the upper end524 on the upper head 516 engages the lower end 526 of the upper slip528. The engagement therebetween pivots the upper slip 528 into theholding position illustrated in FIG. 16A. in this position, the teeth onthe gripping portions 530 and 532 of the upper slip 528 are securelyengaged with the conduit 201 and prevent upward movement of the upperslip 528 and upper head 516.

- The upward movement of the cylinder 470 and upper head 516 carries thebypass valve element 522 upwardly and into sealing engagement with themandrel 422. When the valve element '522 engages the mandrel 422, thepassageway 510 is closed, preventing fluid flow between the packingshell 50.6 and mandrel 422.

Additional pressure applied in the chamber 484 causes the upwardmovement of the cylinder 470 to continue. It will be noted that theupper end of the cylinder 470 engages the lowermost of the packingelements 502 while the now fixed lower abutment 517 on the upper head516 is in engagement with the uppermost of the packing elements'502.Since the cylinder 470 is moving upwardly relative to the abutment 517,the packing elements 502 are deformed outwardly until they are insealing engagement with the conduit 201. The packer assembly 420 is nowin the fully set position in the conduit 201.

The annular valve seat 426 in the valve nipple 425 is constructed sothat a predetermined pressure will shear the valve seat 426 out of thevalve nipple 425, permitting the ball 427 to move downwardly into thewell bore. When the valve seat 427 and ball 425 are forced downwardly,the bore extending through the packer assembly 420 is completely openand any desired operations can be performed below the packer assembly420.

If, after setting the packer assembly 420, the pressure is reduced inthe mandrel 422 and consequently in the chamber 484, the variouscomponents of the packer assembly 420 are retained in the set conditionas illustrated in FIGS. 16A, 16B and 16C. Maintaining the packerassembly 420 set, after the pressure is reduced, is accomplished throughthe split ring retainer 474. The split ring retainer 474, whilepermitting movement of the piston 452 downwardly relative to thecylinder 470, prevents the upward movement of the piston 452 relativetothe cylinder 470 since the split ring retainer 474 wedges against thetapered surface 476 in the cylinder

